/*      $NetBSD: check_bound.c,v 1.2 2000/06/22 08:09:26 fvdl Exp $     */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of Sun Microsystems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Copyright (c) 1986 - 1991 by Sun Microsystems, Inc.
 */

/*
 * check_bound.c
 * Checks to see whether the program is still bound to the
 * claimed address and returns the universal merged address
 *
 */

#include <sys/types.h>
#include <sys/socket.h>

#include <rpc/rpc.h>
#include <rpc/svc_dg.h>

#include <netconfig.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#include "rpcbind.h"

struct fdlist {
        int fd;
        struct netconfig *nconf;
        struct fdlist *next;
        int check_binding;
};

static struct fdlist *fdhead;   /* Link list of the check fd's */
static struct fdlist *fdtail;
static char nullstring[] = "";

static bool_t check_bound(struct fdlist *, const char *uaddr);

/*
 * Returns 1 if the given address is bound for the given addr & transport
 * For all error cases, we assume that the address is bound
 * Returns 0 for success.
 */
static bool_t
check_bound(struct fdlist *fdl, const char *uaddr)
{
        int fd;
        struct netbuf *na;
        int ans;

        if (fdl->check_binding == FALSE)
                return (TRUE);

        na = uaddr2taddr(fdl->nconf, uaddr);
        if (!na)
                return (TRUE); /* punt, should never happen */

        fd = __rpc_nconf2fd(fdl->nconf);
        if (fd < 0) {
                free(na->buf);
                free(na);
                return (TRUE);
        }

        ans = bind(fd, (struct sockaddr *)na->buf, na->len);

        close(fd);
        free(na->buf);
        free(na);

        return (ans == 0 ? FALSE : TRUE);
}

int
add_bndlist(const struct netconfig *nconf, struct netbuf *baddr __unused)
{
        struct fdlist *fdl;
        struct netconfig *newnconf;

        newnconf = getnetconfigent(nconf->nc_netid);
        if (newnconf == NULL)
                return (-1);
        fdl = malloc(sizeof(*fdl));
        if (fdl == NULL) {
                freenetconfigent(newnconf);
                syslog(LOG_ERR, "no memory!");
                return (-1);
        }
        fdl->nconf = newnconf;
        fdl->next = NULL;
        if (fdhead == NULL) {
                fdhead = fdl;
                fdtail = fdl;
        } else {
                fdtail->next = fdl;
                fdtail = fdl;
        }
        /* XXX no bound checking for now */
        fdl->check_binding = FALSE;

        return 0;
}

bool_t
is_bound(const char *netid, const char *uaddr)
{
        struct fdlist *fdl;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (TRUE);
        return (check_bound(fdl, uaddr));
}

/*
 * Returns NULL if there was some system error.
 * Returns "" if the address was not bound, i.e the server crashed.
 * Returns the merged address otherwise.
 */
char *
mergeaddr(SVCXPRT *xprt, char *netid, char *uaddr, char *saddr)
{
        struct fdlist *fdl;
        struct netbuf *callee;
        char *c_uaddr, *s_uaddr, *m_uaddr, *allocated_uaddr = NULL;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (NULL);
        if (check_bound(fdl, uaddr) == FALSE)
                /* that server died */
                return (nullstring);
        /*
         * Try to determine the local address on which the client contacted us,
         * so we can send a reply from the same address.  If it's unknown, then
         * try to determine which address the client used, and pick a nearby
         * local address.
         *
         * If saddr is not NULL, the remote client may have included the
         * address by which it contacted us.  Use that for the "client" uaddr,
         * otherwise use the info from the SVCXPRT.
         */
        callee = svc_getrpccallee(xprt);
        if (callee != NULL && callee->buf != NULL) {
                c_uaddr = taddr2uaddr(fdl->nconf, callee);
                allocated_uaddr = c_uaddr;
        } else if (saddr != NULL) {
                c_uaddr = saddr;
        } else {
                c_uaddr = taddr2uaddr(fdl->nconf, svc_getrpccaller(xprt));
                allocated_uaddr = c_uaddr;
        }
        if (c_uaddr == NULL) {
                syslog(LOG_ERR, "taddr2uaddr failed for %s",
                        fdl->nconf->nc_netid);
                return (NULL);
        }

#ifdef RPCBIND_DEBUG
        if (debugging) {
                if (saddr == NULL) {
                        fprintf(stderr, "mergeaddr: client uaddr = %s\n",
                            c_uaddr);
                } else {
                        fprintf(stderr, "mergeaddr: contact uaddr = %s\n",
                            c_uaddr);
                }
        }
#endif
        s_uaddr = uaddr;
        /*
         * This is all we should need for IP 4 and 6
         */
        m_uaddr = addrmerge(svc_getrpccaller(xprt), s_uaddr, c_uaddr, netid);
#ifdef RPCBIND_DEBUG
        if (debugging)
                fprintf(stderr, "mergeaddr: uaddr = %s, merged uaddr = %s\n",
                                uaddr, m_uaddr);
#endif
        free(allocated_uaddr);
        return (m_uaddr);
}

/*
 * Returns a netconf structure from its internal list.  This
 * structure should not be freed.
 */
struct netconfig *
rpcbind_get_conf(const char *netid)
{
        struct fdlist *fdl;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (NULL);
        return (fdl->nconf);
}